High impedance level

Therefore, the authors concluded that, although direct identification was not available through spectroscopic means, the FAP anion must have participated in the formation of surface layers, which served as protection against sustained decompositions on one hand but were also responsible for the high impedance across the interfaces on the other. These robust surface films might exist on both anode and cathode surfaces and consist mainly of lithium alkyl carbonates because of the low level of HF in the solution. 

For each specimen an average over 122 cycles were taken, but because of the high impedances present, a perturbing voltage of 115 mV was used. This is somewhat higher than the theoretical value arrived at by Meszaros but necessary because of the low level of harmonic signal from the specimens. The visual appearance of each electrode was noted for comparison with the electrochemical data. 

Noble metal connections can reduce the corrosion to an "acceptable" level. This assumption is not true for leads which enter the package from sensors such as micro-electrodes which are characterized by relatively high impedances. The trend for neuroprosthe-tio devices is towards closed-loop control in which the use of high impedance bioelectric sensors will be common. In addition, differing potentials within multi-circuit cables can result in corrosion even when the conductors are fabricated from highly corrosion resistant materials such as MP35N. 

The high impedance of the parallel resonance circuit is transformed to 50 Q nominally by the second variable capacitor. Both variable capacitors are Johan son 5341 which are piston air capacitors with Be-Cu stators and Ag rotors. They work very nicely except for the problem of high voltage breakdown. The dc breakdown under test conditions is listed as 1200 volts at sea level but that number has to be severely derated for radio frequency and altitude. (The latter problem is serious at Los Alamos where the atmospheric pressure is 590 mm Hg and the altitude correction to the breakdown is about 10%.)... 

An interesting variation of this circuit is the cascode amplifier shown in Fig. 9.13. Here, the drain load is exchanged for a constant-current generator. Theoretically this gives infinitely high impedance thus yielding a very high level of amplification. 

What impedes interaction are the extremely unfavourable conditions prevailing in fibrous suspensions, such as very high dilution levels, strong turbulence and high shear forces, short contact times with fibres and, not to forget, anionic trash - all of which counteract optimal adsorption of chemicals onto the fibres. 

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